The present invention relates to a parking lock state releasing apparatus that is used in a vehicle with a vehicle transmission control device for shifting the connecting state of the vehicle""s transmission through electric control for releasing a parking lock of the transmission when the transmission control device is incapable of controlling the transmission.
Conventionally, a shift-by-wire type vehicle transmission control device has been proposed, which shifts the connecting state of a transmission through electric control. In this type of transmission control device, when a shifting body located in a passenger compartment is operated, the operating state of the shifting body is detected as an electric signal. An actuator for shifting the connecting state of the transmission in response to the detected signal is then operated. This transmission control device makes it unnecessary to provide a mechanical structure, such as a link mechanism, and the transmission is easily minimized. It is thus possible to arrange the shifting body and the accessories in the passenger compartment as desired. This makes the passenger compartment comfortable.
When the transmission is shifted to the parking state (the parking range), a parking lock is activated. More specifically, in the parking state, the transmission engages a parking lock gear, which is located in an output shaft system of the transmission, with a parking lock pole. This mechanically locks the wheels of the vehicle.
However, if the electric controlling of the transmission by the transmission control device is hampered by insufficient battery voltage or other problems when the transmission is in the parking range, the parking lock state of the transmission cannot be changed to the release state. This causes the disadvantage that the vehicle cannot be moved.
The present invention addresses this problem. Accordingly, it is an objective of the present invention to provide a parking lock state releasing apparatus that releases a parking lock state of a transmission even when controlling of the transmission by a vehicle transmission control device is hampered.
To achieve the foregoing objective, an embodiment of the present invention provides a parking lock state releasing apparatus of a vehicle that has a transmission control device. The transmission control device has a shifting body and detects the operating state of the shifting body. The transmission control device shifts the connecting state of the transmission based on the detection result. The parking lock state releasing apparatus for the vehicle includes a releasing switch, which is located in a passenger compartment. An ignition drive device generates gas by causing ignition response to operation of the releasing switch. The parking lock state of the transmission is changed to the release state using the pressure of the gas.